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Amiga Collections: MegaDisc
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MegaDisc 30 (1992-10)(MegaDisc Digital Publishing)(AU)(Disk 1 of 2)[WB].zip
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MegaDisc 30 (1992-10)(MegaDisc Digital Publishing)(AU)(Disk 1 of 2)[WB].adf
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Articles
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HardDisks_&_Scram
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HardDisks_&_Scram
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1992-10-05
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7KB
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118 lines
Hard Disc Drive Experiences
Peter Youll
Ed: Here's a cautionary tale about when an old hard disc dies, and a new
one won't come to life.
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A couple of years ago I wrote a review for Megadisc about an A500 1Mb
memory expansion, disc controller and 40Mb disc put together by a group in
Adelaide going by the name of XEL. At the time the XEL was the most
economical option for adding to the abilities of the A500, and it had a
dramatic effect on the usability and the amount of use made of our Amy.
The disc had plenty of capacity for our needs and was never more than about
half full. The extra 1Mb of memory was enough for any application we ever
used. My only complaint with the system was the noise made by the disc,
however this was tolerable.
About 2 years on, the cooling fan in the disc box began to make growling
noises, and it had to be replaced. A couple of months ago, the disc began
to do likewise, accompanied by miscellaneous bangs and clunks, and many
read and write errors. I managed to back the whole disc up before it
became inaccessible, and refused a low level format. Then the real fun
began.
The original disc was a Seagate ST251 (5¼", half height, 40Mb, 28msec
access) with an ST502 interface. The connection from the memory expansion
in the side of Amy was by way of a 25 core ribbon cable, which was
connected to a converter card and thence to an Opti ST502 controller card
inside the box with the power supply and disc. Fortunately several old PC
clones at work were being upgraded at the time, and an NEC disc (3½", half
height, 42Mb, 28msec access) left over from the process quickly found a new
home in the XEL box. After about a week of toil with configuration and low
level formatting and some expert assistance (thank you Chris Ralph), the
NEC was soon at work, and making far less noise than the Seagate.
All went well until a Saturday morning a couple of weeks later - breakfast
was interrupted by what sounded like a running tap in the study. There are
no taps in the study! The NEC was having a head crash! I had not done a
backup for about 2 weeks, and was part way through a large assignment. The
only copy of it was on the disc! I attempted a full backup, but the noises
were getting worse, and the frequency of read errors was increasing
rapidly. After much struggle, late on Saturday afternoon I did manage to
get the file containing the assignment into RAM: then onto a floppy, and
minutes later the scrapping noises became grinding, and the disc had to be
powered down for the last time.
What to do now? I had to have the assignment completed in 2 weeks. On
Sunday morning I first called around the computer shops and found that a
new ST506 interface disc could not be obtained - they are no longer made.
The only options were to try and find a second hand ST506 disc, attempt to
have the Seagate repaired, or to go for the Scram500 and a SCSI disc that I
had read about in Megadisc. The first two could have taken weeks, and I
didn't have that long. How fortunate that my spouse had obtained a casual
teaching position for the rest of the year, making the Scram an option we
could afford!
What to do? Ring Tim Strachan of course! I called the Megadisc number
expecting to leave a message with the answering service, but Tim answered
in person. He undertook to try to get hold of a Scram500 expansion,
leaving me to hunt down a suitable disc about the same capacity as the
recently deceased NEC. The former was obtained on loan later that day from
the designer of the Scram, Norm Jackson at Annandale, who recommended a
Quantum 52Mb disc as the best bet. The latter proved to be unobtainable in
Sydney on a Sunday, or any other day. There were no small Quantum drives
of any capacity available in all the computer suppliers in Sydney. Gloom!
On Monday morning I called Tim again, and he was confident he could get a
Quantum disc - from Bunbury WA! Sure enough, it arrived at home early on
Tuesday morning - what a service! I had to wait until that night to fit
the disc into the XEL box, complete with SCSI cabling scrounged from
various sources at work. Then the moment of truth - turn on the power and
NOTHING, except for a slight ticking noise from the power supply. The volt
meter showed all to be OK, but the disc didn't run.
The answer
Next day calls to Tim and the supplier in Bunbury suggested that I had a
dud disc, and that a replacement would be sent that night. Then by chance
I happened on an open PC at work, and tried plugging a spare power plug
into the Quantum disc - it spun up! There must be something wrong with my
power supply. I mentioned this to an expert at work, and it all fell into
place - a switch mode power supply won't work unless the load is within a
specified range. The Quantum disc has such a low load on the 5 volt side
that the power supply wouldn't provide sufficient current to the 12 volt
side to get the disc spinning. Addition of a heat sink 15 ohm resistor to
the 5 volt load did the trick, and the disc ran and continues to do so -
very quietly.
Back home again, connect the disc box to the Scram500, use the supplied
ScramPrep program to partition the disc, load everything from backup, and
Amy was back in business. And so far it has not cost a thing! We await
the Mastercard bill with trepidation.
Later I swapped the loaned Scram for a new one with 2Mb on board, and have
changed the startup sequence to use the hard disc to boot, which could not
be done with the XEL controller. The disc has worked faultlessly, and is
much quieter and a lot faster than either the Seagate or the NEC. It also
has the advantage of having a future - the SCSI interface should be around
for sometime, and the disc could be fitted to an A3000 - eventually. The
location and shape of the Scram500 expansion is a problem for me at least -
it gets in the way of my left hand due to my 'few finger' method of typing.
A real typist would not have a problem.
In summary - the Scram500 + disc is highly recommended, as is the service
provided by Megadisc. And I got the assignment completed on time.
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